Impacts of White-Nose Syndrome Observed During Long-Term Monitoring of a Midwestern Bat Community

Abstract

White-nose syndrome (WNS) is an emerging fungal disease suspected to have infected Indiana caves in the winter of 2010–2011. This disease places energetic strains on cave-hibernating bats by forcing them to wake and use energy reserves. It has caused >5.5 million bat deaths across eastern North America, and may be the driving force for extinction of certain bat species. White-nose syndrome infection can be identified in hibernacula, but it may be difficult to determine whether bats in a particular area are affected if no known hibernacula exist. Thus, our aim was to use long-term monitoring data to examine changes in a summer population away from hibernacula that may be attributable to WNS effects during winter. We used capture data from a long-term bat-monitoring project in central Indiana with data from 10 repeatedly netted sites consistent across all reproductive periods. We modeled capture data by WNS exposure probability to assess changes in relative abundance of common species and reproductive classes as WNS exposure probability increases. We base exposure probability on a cokriging spatial model that interpolated WNS infection from hibernaculum survey data. The little brown bat Myotis lucifugus, the Indiana bat M. sodalis, and the tri-colored bat Perimyotis subflavus suffered 12.5–79.6% declines; whereas, the big brown bat Eptesicus fuscus, the eastern red bat Lasiurus borealis, and the evening bat Nycticeius humeralis showed 11.5–50.5% increases. We caught more nonreproductive adult females and postlactating females when WNS exposure probabilities were high, suggesting that WNS is influencing reproductive success of affected species. We conclude that, in Indiana, WNS is causing species-specific declines and may have caused the local extinction of M. lucifugus. Furthermore, WNS-affected species appear to be losing pups or forgoing pregnancy. Ongoing long-term monitoring studies, especially those focusing on reproductive success, are needed to measure the ultimate impacts of WNS.

Observed Resiliency of Little Brown Myotis to Long-Term White-Nose Syndrome Exposure

“…Similar declines in little brown myotis summer colonies and activity on the landscape have also been noted throughout the Northeast (Ford et al 2011;C. Herzog, A. Bennett, and S. von Oettingen, personal communication), Mid-Atlantic, and Midwest regions (Francl et al 2012;Pettit and O'Keefe 2017), with many colonies and populations now extirpated. However, despite extensive declines, some localized populations of little brown myotis are persisting (Dobony et al 2011;Reichard et al 2014).…”

Multiscale model of regional population decline in little brown bats due to white‐nose syndrome

“…The disease, which has been documented in multiple temperate bat species (Langwig et al, ), negatively impacts bats via dehydration and excessive fat depletion by interrupting periods of torpor during hibernation (Bernard & McCracken, ; Meteyer, Barber, & Mandl, ; Reeder et al, ; Warnecke et al, ) and disrupting electrolyte balance (Cryan et al, ). Survival rates of infected bats vary by species and colony, and while there is evidence that resistance may be developing in some colonies (Langwig et al, ), the fungus is spreading across the continent and abundances of multiple species continue to decline (Frick et al, ; Pettit & O'Keefe, ). Spatial spread of Pd among hibernacula and overwinter bat mortality have primarily been studied independently, but susceptible bat population dynamics are likely to be highly dependent on the mechanisms linking these processes.…”

“…be developing in some colonies , the fungus is spreading across the continent and abundances of multiple species continue to decline Pettit & O'Keefe, 2017). Spatial spread of Pd among hibernacula and overwinter bat mortality have primarily been studied independently, but susceptible bat population dynamics are likely to be highly dependent on the mechanisms linking these processes.…”

Galleria mellonella experimental model for bat fungal pathogen Pseudogymnoascus destructans and human fungal pathogen Pseudogymnoascus pannorum

“…White-nose syndrome (WNS) is an epizootic disease responsible for the deaths of more than 5 million bats in North America since its first discovery in 2006 [1,2]. The latest surveillance and modeling data suggest that WNS is likely to lead to the regional extinction of some bat species in the United States while the disease remains well-tolerated among the European bats [3,4].…”